Control of furnaces



May 29, 1928. 1,671,599

' E. McLEAN CONTROL OF 'FU'RNACES Filed Sept. 10, 1923 2 Sheets-Sheet l Q Q 6 I INVENTOR. Q: BY 2 W 7" T 44.44 TTORNEYS May 29, 1928.

E. MCLEAN CONTROL OF FURNACES Filed Sept. 10, 1925 2 Sheets-Sheet I N VEN TOR. W

fig BY W @ORNEYJ '1 on the foundation of the boiler.

Patented May 29, 1923.

uuiree stares Parser or" its.

- EIIIBUBY MCLEAN, OF BROOKLYN. NEW YORK, ASSIGNOR TO THE ENGINEER COM- PANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

CONTROL OF FURNACES.

My invention moreparticularly relates to the control of a furnace, in which a stoker is used. In accordance with my invention, the speed of the-Stoker is independent of the character ofthe fuel bed, but is varied in accordance with a functionof the furnace, as

- for example, by the load on the boiler, by the supply of air to the furnace or by the area of the outlet for the furnace gases where substantially constant pressure is maintained-in the furnace for varying rates of combustion.

My invention consists of certain novel parts and combinations of parts particularly pointed out in 'theclaims.

The following is a description of an apparatus for. carryingout my invention in the form at present preferred by me, but it will be understood that various modifications and changes may be made without departing from the spirit of my invention and without exceeding the scope of my claims.

Myinvention will best be understood by reference'to the accompanying drawings in which Figure 1 is a diagrammatic view of a steam boiler and furnace, and the parts associated therewith, for carrying out my in vention; Fig. 2 is a sectional detail view of a pressure-operated device for controlling.

the stoker and Fig. 3 illustrates diagrammatically a modified form of my invention.

Like reference characters indicate like parts throughout the drawings. I

Referring now to the drawings, 10 is a steam boiler, the furnace for which is indicated at 11., The furnace is supplied with fuel by, an automatic stoker 12 which is driven by a steam engine 13 supplied with steam through a pipe 14 from the boiler 10. The engine shaft 15 is provided with-a pulley 16. y A shaft 17 is driven by a belt 18 which passes OX/7E1 the pulley 16 andover a pulley 19 on theshaft 17. The shaft 17 takes its hearings in standards 20, supported The inner end of the shaft 17 is provided with a bevel gear 21 which meshes with a bevel gear 22 secured on the operating shaft 23 for the Stoker. v

In accordance :withuny invention. means are provided for rendering the speed of the stoker independent of the'load thereon. In

the form shown, the motor 13 for operating the stoker drives a pump 24 through belt 25, engaging a pulley 26 on the motor shaft 15 .and a pulley 27 on the pump shaft 28, respectively. The pump is preferably connected to an open fluid circulating system indicated generally at 29 and comprising .a closed supply tank 30 for any suitable fluid, such as water, the tank being connected to one side of thepump by a pipe 31 and also being connected by a pipe t0 the other side of the pump. The motor which operates the stoker, therefore, drives the pump, which in turn circulates the fluid in the open circulating system 29 at a speed and, pressure varying with the speed of the motor for the stoker.

In accordance with my invention, means are. provided for varying the supply of energy to. the .stoker motor in accordance with the speed of the motor. In the form shown in Figs. 1 and 2, a pressure chamber 33 communicates with the pipe 32 through a pipe 34. The pressure chamber 33 is enclosed by a casing head 35, the lower side of which is closed by a flexible diaphragm 36. The movement of the diaphragm 36 actuates a valve 37 located in a valve head 38 in the pipe 32. In the form shown, the valve 37 is provided with two valve members 37 which engage valve seats 39 in the valve head 38. The ends of the pipe 14, as illustrated in Fig. 2, which are connected to the valve head 38,- communicate with chambers 40 and 41, respectively, which are separated from each other the valve 37 when the valve is in the closedposition illustrated in Fig. 2. The valve head 38 is provided with a chamber 42 which communicates with the chamber 41 through a passage 43. hen the valve 37 is in theopen position, communication is afforded between the chamber 40 and the chamber 42 which is, in turn, in communiat any desired pressure, the stem 44 is pivotedfat45 to an arm 46, one end of which is pivoted as at '47 to a bracket 4" on ,the casing head. One end of a spring 48 is con nected to the opposite end of the arm 46,

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preferably through a link member 49, the opposite end of the spring 48 being attached to an adjustable screw 50 which is received in a tapped opening in a bracket 51 carried on the casing head. The adjustment of the screw member 50 is made by a thumb nut 52. By varying the position of the screw 50, the tension on the spring 48 may be varied and the pressure within the pressure chamber 33, which is necessary to operate the valve member 87, may be correspondingly varied.

The operation of the foregoing apparatus tends to maintain the speed of the motor for operating the stoker constant, and independ ent of the load on the stoker. Any increase in speed of the engine 13 will produce a corresponding increaz-"ie in the speed of the pump thereby increasing the pressure in the closed circulating system 29, and corrcs dingly increu t pressure in the pr The diaphragm 36 chamber (12%. will, therefore, be depressed, and the valve member 3? partially closed to decrease the steam supply to the steam engine 13, thereby bringing the speed of the engine back to normal. of the steam engine 13 will increase the steam supply to the engine and bring the speed of the engine back to normal.

In accordance with my invention, the speed of thestoker which is independent of thcload on the stoker, is varied in any desired manner, either manually or automatically. In the form shown in Fig. 1, the pipe 32 for-the closed; circulating system 29 is provided with a valve 53 which is operated by an arm 55%, which arm may be operated either manually or automatically by a function of the furnace, and here shown as the furnace draft. In the form shown, the furnace 11 is equipped with a pressure regulator 55 which may be of the same character as that illustrated in my Patent No. 1,355,157 which was issued October 12, 1920, and which need not. therefore, be specifically described. Briefiy, the pressure regulator comprises a pivoted regulator plate 55, the

movement of which controls, through a valve 56, the supply of fluid from a source of fluid pressure supply represented by the pipe 57 tothe lowerside of a cylinder 58, through a pipe 57, the upper end of the cylinder pref erably being permanently connected to the source 57 of fiuid'pressure through a pipe 59. An operating chain 60 is connected to the piston 61 within the cylinder 58, and in the form shown, operates the flue damper 62 and the arm 54: The chain 60 is connected at 60 to a'branch 63 which passes over a pulley 64' and connected at 65 to an arm 66 secured on the damper shaft 67. branch 680f the chain passes over pulleys 69 andTQ and 'is connected at 71 to the arm 54, the end of the branch chain 68. .)referabl v being equipped with a counterweight 68 Similarly a decrease in speed A second which moves the chain and the associated parts in the direction opposite to the direction in which they are moved by the piston 61. \Vhen the damper (32 is rotated anticlockwise as viewed in Fig. 1, corresponding to an increase of combustiomthe arm 54 is moved upwardly thereby increasing the opening of the valve 53 and decreasing the pressure in the fluid pressure system and in the chamber 33, and opening the valves 37 increasing the flow of steam to the stoker motor and increasing the feed of fuel. When the damper 62 is rotated clockwise, condi tions just discussed are reversed, and the feed of fuel decreased.

In accordance with my invention, the speed of the motor and of the stoker is mdependent of the load on the stoker and is not varied, as is usually the case, by the depth of fuel bed and the character of fuel. At the same time, the speed of the motor and of the stoker is varied in any desired manner, either manually or automatically, the latter preferably in accordance with variations in the draft in the furnace.

In Fig. 3 I haveillustrated diagrammatically a modification whereinthe stoker is operated by an electric motor 13; In the arrangement here illustrated the boiler and furnacewith its Stoker, the pressure device for operating the fine. damper, and the open circulating system are all the same as those illustrated and descril'ied in Fig. 1, and the same reference characters are app.liedthoreto. In the arrangement here shown, the stoker is operated by a motor 13 to which current is delivered from supply conductors indicated at 7 2. The motor 13 operates the pump 24 for the closed circulating system 29 by connections the same as those described in connection with Fig. 1; In the circuit of the motor is a rheostat 73 provided with contacts 74, over which passes an arm 75 which forms one member of" bell crank, the other member 7 6 of which is connected to and operated the steiir44 which is connected to the diaphragm4.6'111 the same manner as is the steingl, shown in,

Fig;

Any increase in speed of the motor 13 brings about a corresponding increase in the speed of the pump 24 and of the'pressure in the closed circulating system 29, thereby operating the stem i l and. the arm in a direction to include additional resistance in the circuitof the motor, thereby bringing the speed of the motor back to normal, On the other hand, a decrease in speed of the motor brings about the reverse operation of the parts from that just described, thereby decreasing the amount of resistance included in the circuit of the motor," and thereby bringing'it's speedbackto normal.

It will be evident without further discussion that the movement of'the arm 54 and of the, valve 53 operated thereby, is or may be produced'in the same manner as described in connection \vithFigure 1., and its move-.

said stoker, a pump driven by said motor for creating fluid pressure, means controlled by the said pressure for varying the supply of energy to saidmotor and independent means forvarying said pressure.

2. In combination, a furnace, a stoker for feeding fuel thereto, a motor for operating said stoker, a pump driven by said motor,

a circulating fluid pressure system connected to saidpump, and a pressure-operated device connected to said circulating fluid pressure system and controlling the supply of energy to said motor.

3. In combination, a furnace, a stoker for feeding fuel thereto, a motor for operating said stoker, a pump driven by said motor, a

circulating fluid pressure system connected to said pump, a pressure-operated device connected to said circulating fluid pressure system and controlling the supply of energy to said motor and means independent of said pump for varying the pressure on said pressure-operated device.

4. In combination, a furnace, a stoker for feeding fuel thereto, asteam engine for op erating said stoker, a'pump operated by said engine, regulating means for maintaining the pressure of the furnace gases substantially uniform for varying rates of combustion, and a pressure-operated device for controlling the supply of steam to said steam engine, and under the joint control of said pump and of said regulating means.

5. In combination, a furnace, a stoker for feeding fuel thereto, a motor for operating said stoker, a source of energy supply for said motor, a pump operated by said motor, means operable by variations of speed of said pump tending to maintain the speed of said motor substantially constant, and means operable in accordance with variations in furnace pressure to vary the speed of said motor.

6. In combination, a furnace, a stoker for feeding fuel thereto, a motor for operating said stoker, an open fluid pressure system, a pump driven by said motor for forcing fluid through said system, means controlled by the pressure in said system for varying the supply of energyto said motor, and means for controlling the discharge of fluid from said system.

7. In combination, a furnace, a stoker for feeding fuel thereto, a motor for operating said stoker, an open fluid pressure system, a pump driven by saidmotor for forcing fluid through said system, means controlled by the pressure in said system for varying the supply of energy to said motor, and means for controlling the discharge of fluid from said system in accordance With a function-of the furnace.

'8. In combination, a furnace, a stoker for feeding fuel thereto, a motor for operating said stoker, an open fluid pressure system, a pump driven by said motor for forcing fluid through said system, means controlled by the pressure in said system for varying the supply of energy to said motor and tending to. maintain the speed of said motor substantially constant, andfmeans for controlling the discharge of fluid from said system.

9. In combination, a furnace, a stoker for feeding fuel thereto, a motor for operating said stoker, a pump driven by said-motor, means operable in response to the operation of said pump tending to maintain the speed of said mot-or substantially constant, regulating means for maintaining the pressure of the furnace gases substantially uniform for varying rates of combustion, and means operable in accordance with movements of said regulating means for varying the speed of said motor.

10. In combination, a furnace, a stoker for feeding fuel thereto, a motor for operating said stoker a pump driven by said motor for creating fluid pressure, means controlled by the said pressure for varying the supply of energy to said motor, and means operable in accordance With a function of the furnace for varying said pressure.

11. In combination, a furnace, a stoker for feeding fuel thereto, a motor for operating said stoker, a fluid pressure system, a pump operable by said motor for creating pressure in said fluid pressure system, means for controlling the energy supply to said motor, a fluid pressure operated device operable by the fluid pressure in said system for directly actuating the energy controlling means. and independent means for controlling discharge of fluid from said fluid pressure system and thereby controlling the pressure therein.

12. In combination, a furnace, a stoker'for feeding fuel thereto. a steam engine for operating said stoker, a fluid pressure system, a pump operable by said steam engine for creating pressure in said system, valve means for controlling the supply of steam to said engine, a fluid pressure operated device operable by the fluid pressure in said systerm for directly actuating said valve means, and independent means for controlling discharge of fluid from said fluid pressure system and thereby controlling the pressure therein.

13. The method of operatinga furnace in whichlai oker and Stoker motorare used for feeding tfi'iel were furnace and comprising afluic'l pressure systeln, which Consists in yarying'the pressure in said fluid pressure system in accordance with the speed of the motor, controlling the supply of energy to said motor in accordance with the pressure in said system, and controlling the pressure in said system in a ccordance with a functionio't' the il'u'nace 145. The method of operating a furnace in which a stoke]: and stoker motor are used ifeedjing fuel to the furnace and comprisinc a'fi'uid pressure system, which consists in Varying the pressure in said fluid pressure system in accordance with the speed of the motor, controlling the supply of energy to said motorin accordance with the pressure in saidsystenr and in such a wayas to tend to r'n aintain the speed of said motor subste'nti'ally constant, and controlling the pressure in said system in accordance with a function o f thefurnace. i

1.5. In combination a furnace, a stokerfor feeding fuel thereto, a motor for operating said Stoker, and fluid pressure means for maintainingthe speegjl of, said motor substantially constant with varia ble resistances to the feeding mechanism, and independent means for varying the speed of said motor by controlling, said fluid pressure means.

16. In con'lbinatioma furnace, a stokerfor feeding; fuel thereto,a motor for operating said stoker, a pump driven by said. motor for creating fluid pressure, means. controlled by the said pressure for Varyingthe supply of energy to said notoi: for maintaining the speed of the 1 n( tor substantially constant for varying resistances tothe feeding mech-. anisin, and independent means for varying said pressure.

EM'BURY Men-EAR, 

